1. Field of the Invention
This invention is drawn to the field of fluid mechanics, and is directed more particularly to an electromagnetically activated compliant wavy-wall, operable to control drag and noise of a body moving relative to a fluid medium.
2. Description of the Prior Art
Previous wavy-wall devices have included a number of mechanical and fluidic methods to produce distortion and motion of a surface immersed in a fluid medium. Imbedded piezo-electric transducers underlying layers of miscoelastic fluids and electro-rheological fluids, surface layers of polymer films with properties similar to piezo-electric elements, and a large number of mechanical and thermal devices, have been used in controlling in surface geometry and movement of compliant walls adjacent to flowing fluid. A primary objective of such devices is drag reduction. However, in certain instances it is desirable to increase drag, or otherwise alter the boundary layer of a body operating in a fluid. The noise, or acoustic signature, of a body can be modified in this manner.
In addition to mechanical action, it is possible to control the noise and turbulence characteristics of a body operating in a fluid medium via electrical and magnetic means. Previous methods of producing magnetic, electric, and electromagnetic forces in adjacent fluid flows used only static surfaces at which the magnetic, electric and/or electromagnetic forces were produced.